Percutaneous in situ or on-site treatment of malignant breast tumors by laser therapy is being developed in part due to the fact that breast cancer is being detected at earlier stages because of the increasing number of women receiving mammograms annually. If breast cancer and other cancers or tumors are detected in early development, the tumor can be effectively treated using an ablative agent such as laser energy.
Image-guided laser treatments of malignant tumors such as, breast, liver, head and neck tumors, have been in development for more than a decade. For example, U.S. Pat. No. 5,169,396 (“the '396 patent”) issued to Dowlatshahi is directed to the interstitial application of laser radiation therapy to tumor masses and is incorporated herein by reference. In general, the apparatus of the '396 patent includes a probe having a thin metallic cannula for insertion into a tumor mass, a laser for generating light having a chosen wavelength and intensity, and an optical fiber for receiving and transmitting the laser light to the tumor mass, whereby the optical fiber is inserted into the cannula such that a chosen physiologically acceptable fluid can flow coaxially between the cannula and the optical fiber. In addition, a heat sensing member is inserted adjacent into the tumor mass for monitoring the tumor temperature. The devitalized tumor is gradually cleared by the body immune system and within six months is replaced with a scar.
However, the treatment of tumors and in particular the specific treatment of breast tumors is generally known to be more difficult due to the fact that it is difficult to determine the three dimensional boundaries of the tumor, and thus, difficult to determine when all of the tumor has been destroyed.
To address this problem, medical researchers have utilized a variety of tumor mass identification techniques for determining the size and outer boundaries of a tumor mass. Examples of conventional identification techniques that have been employed in combination with laser therapy are magnetic resonance imaging, radiographic and sonographic techniques. When utilizing an identification technique, coordinates identifying the actual size of the tumor mass are determined by using stereotactic techniques or the like.
To solve this problem, at the time of laser treatment, markers may be placed in a 0.5–1.0 cm zone of “normal” tissue to demarcate the zone in which the tumor extension may exist. This ring of “normal” tissue is equivalent to a cuff of tissue engulfing the tumor removed during conventional surgery (i.e., a lumpectomy). The boundaries of the ring surrounding the tumor are marked at 3, 6, 9 and 12 o'clock locations by inserting metal markers through a needle. The insertion points are precisely determined by known stereotactic technique using a commercially available stereotactic table.
Such marker elements are the subject of U.S. Pat. No. 5,853,366 (“the '366 patent”) issued to Dowlatshahi is directed to a marker element for interstitial treatment. In general, the '366 patent discloses a marker element that can be positioned wholly within the body of a patient by utilizing a guide member having a guide path so as to mark a tumor mass of interest. The marker element is made of a radiopaque material which includes any material that is capable of being detected by conventional radiographic, sonographic or magnetic techniques.
Medical researchers have also employed non-surgical techniques other than laser therapy to treat breast tumors. For example, radio frequency, microwave, and cryogenic-related treatments have been attempted.
The present invention recognizes the above described problem, that is, to provide a non-cutting treatment for cancer and in particular for breast cancer that can be relied upon to determine when the entire tumor is effectively destroyed. There is accordingly a need for a non-cutting breast cancer therapy which addresses this problem and the problems arising from the difficulty in determining whether the tumor is completely destroyed.